1. Field of the Invention
The present invention relates to an electro-optical element comprising a liquid crystal, such as a smectic liquid crystal or nematic liquid crystal, which is inserted and gripped between two substrates. More particularly, the present invention relates to an electro-optical element having a uniform space of an order of .mu.m and a process for the preparation thereof. Furthermore, the present invention relates to a technique of securing two substrates, between which a liquid crystal is sealed, by a spot adhesive.
2. Description of the Related Art
A liquid crystal electro-optical element comprises two glass substrates having formed on the surfaces thereof a driving transparent electrode film and an oriented film for arranging molecules of a liquid crystal, which are arranged to confront each other with a certain space therebetween, and a liquid crystal sealed in the space.
A liquid crystal electro-optical element utilizing a ferroelectric liquid crystal showing a chiral smectic C phase has recently been developed (see, for example, Japanese Unexamined Patent Publication No. 56-107216). More specifically, a liquid crystal having a chiral smectic C phase, such as p-desiloxy-benzylidene-p'-amino-2-methylbutyl cinnamate or p-hexyloxybenzylidene-p'-amino-2-chloropropyl cinnamate, has a liquid crystal molecule arrangement having a spiral layer structure. When the liquid crystal is injected between two substrates arranged to confront each other with a space narrower than the spiral period, the liquid crystal molecules lose the spiral structure and bistable states are produced by influences of the oriented film. By utilizing the ferroelectric characteristic of the liquid crystal molecules, the bistable states are changed over to each other at a high speed by application of a voltage to drive the element. When the voltage is removed, the liquid crystal molecules retain one of the bistable states. In short, the liquid crystal has a memory characteristic.
As another known technique, there can be mentioned a technique of bonding and securing glass sheets by using an encapsulated adhesive, as disclosed in Japanese Unexamined Patent Publication No. 57-29031. However, this technique is not preferred because the bonding force of the adhesive is low and the adhesive has bad influences on a liquid crystal.